Define properties as annotations for dynamic property group
Hi your post is the closest to the issue that I'm having, and it seems like you've resolved your problem, I'm just not sure how the structure of your class can relate to the structure of the class in my problem that's throwing the error
I keep getting these annotation-type warnings which I understand are common but not breaking for addons that have compatibility 2.8 and 2.7, however, when trying to run blender in the background it becomes breaking.
Warning: class WM_OT_import_modal contains a property that should be an annotation!
c:\Users\Willard\Desktop\blender\2.82\scripts\addons\sketchfab_init_.py:1648
assign as a type annotation: WM_OT_import_modal.gltf_path
assign as a type annotation: WM_OT_import_modal.uid
You are using the latest version(1.3.1)
ERROR (wm.operator): c:\b\win64_cmake_vs2017\win64_cmake_vs2017\blender.git\source\blender\windowmanager\intern\wm_event_system.c:1486 wm_operator_invoke: invalid operator call ‘WM_OT_import_modal’

Below is the class in the addon throwing the error.
class ImportModalOperator(bpy.types.Operator):
    bl_idname = &quot;wm.import_modal&quot;
    bl_label = &quot;Import glTF model into Sketchfab&quot;ltf)
    bl_options = {'INTERNAL'}

    gltf_path = StringProperty()
    uid = StringProperty()

It would seem I just need to assign the properties: “gltf_path” and “uid” as type annotation to fix my error. But I can not conceive how to do this